1. Field of the Invention
The present invention relates to a vehicle control system and, more particularly, pertains to a ground control system for agricultural or like use. The present invention can also pertain to spreaders for agricultural use, other materials, or ordinary road salt.
2. Background of the Invention
In the application of dry bulk material to the ground for purposes of fertilizing, weed control and soil conditioning or ice control, the most prevalent method of application has been to maintain a preselected ratio of metering conveyor speed of a spreader to travel speed of the vehicle. In the 1960's, the common method was to mechanically connect the conveyor drive to a member of the vehicle propulsion system such as the transmission or geared to the wheel. This method provided that any increase in travel speed produced a proportional increase in metering conveyor speed but with the two disadvantages being the high cost of maintenance of mechanical drives for transmitting the prime moving torque and the inability to speedily change the ratio of metering conveyor speed to travel speed of the vehicle.
The above problems were overcome by converting to hydraulic drive control, as illustrated in U.S. Pat. No. 3,441,039, which proved successful with the exception that the hydraulic drive control was highly wasteful of energy through consumption of power for the control and limited throughput of materials.
The energy consumption problem was overcome by U.S. Pat. No. 3,703,810 which reduced energy consumption and expanded the throughput limitations, but the hydraulic bypass flow control problem was still prevalent with energy being over utilized. With the rapidly increasing cost of energy, the system was not energy-efficient.
The present invention overcomes the disadvantages of the prior art by providing a ground control system which exhibit maximum efficiency of energy utilization and, more importantly, adjusts the height of the feedgate dependent on the conveyor speed of the spreader and the ground speed of the vehicle. The system provides for the saving of energy.